正确填充字节缓冲区

Question

恒定字节来。可能会增加时间，以便正确填充缓冲区，但是必须保证接收速度快。如何正确填充缓冲区？在初始和最终符号上显示Posik？ 可以设定包装的长度吗？在Java中，它是这样的：packet.getLength（）

private async Task ReadAsync(CancellationToken cancellationToken)
    {
        Task<UInt32> loadAsyncTask;
        uint ReadBufferLength = 30;
        // If task cancellation was requested, comply
        cancellationToken.ThrowIfCancellationRequested();
        // Set InputStreamOptions to complete the asynchronous read operation when one or more bytes is available
        dataReader.InputStreamOptions = InputStreamOptions.Partial;
        // Create a task object to wait for data on the serialPort.InputStream
        loadAsyncTask = dataReader.LoadAsync(ReadBufferLength).AsTask(cancellationToken);
        // Launch the task and wait
        UInt32 bytesRead = await loadAsyncTask;
        if (bytesRead > 0)
        {
            String dataBufferStr = dataReader.ReadString(bytesRead);                  
        }
}